Already finding it difficult to deal with having two young children – quiet but impressionable Sarah (Frankland), and Jonah (Fallica), who has an undiagnosed developmental disorder – Marlo (Theron) is pregnant with an unplanned third child. With her husband, Drew (Livingston), working long hours or having to travel a lot, Marlo is often on her own, and finding it increasingly hard to be heavily pregnant and a full-time mother to pre-teens. When the baby, Mia, is born, the pressure becomes too much, and a meltdown at Jonah’s school brings Marlo to the realisation that she needs help. Acting on an offer from her brother, Craig (Duplass), to pay for a night nanny, Marlo is surprised to find a young woman called Tully (Davis) arrive one night and begin to make her life a lot more easier. The two women forge a strong bond, and Marlo finds herself with a new lease of life. But one night, Tully is uncharacteristically miserable, citing an issue with her roommate. At her suggestion, she and Marlo head into the city for a night on the town, a decision that is to have serious consequences…

The fourth collaboration between director Jason Reitman and writer Diablo Cody – after Juno (2007), Jennifer’s Body (2009), and Young Adult (2011) – Tully is a heartfelt look at the narrow ledge some mothers find themselves traversing when motherhood proves overwhelming. Marlo appears to have been struggling ever since Jonah was born, both with his behavioural problems, and her own expectations of being a mother. With pressure from the outside competing with pressure from within, Marlo’s inability to manage consistently or even occasionally is a given, and Cody’s script has fun piling on heap after heap of setbacks and misfortune, while placing Marlo in the kind of family unit where her getting through the day is a major achievement. Is it anyone’s fault? Perhaps, but Cody and Reitman aren’t about assigning blame, they’re about rescuing Marlo from the mire she’s trapped in. And so we meet Tully, the damsel in shining armour, Marlo’s saviour and nascent best friend. As their friendship grows and becomes overly important in helping Marlo cope – she literally blossoms before our eyes – the bond between mother and daughter slips sideways until it’s about mother and nanny instead. There’s a love affair of sorts here, but it’s refreshingly chaste and wonderfully done.

The movie is blessed by two outstanding performances from Theron and Davis. For most of the movie, Theron – who gained nearly fifty pounds for the role – appears unflatteringly, big and sweaty and looking red-eyed and exhausted. It’s a powerful, nuanced portrayal, with subtle flourishes throughout, but she’s matched by Davis, whose own performance is flecked with delicate little touches, a look here, a twinkle there. Together, the two actresses are mesmerising to watch, and dominate the narrative. Inevitably, with two such strong female roles at the movie’s centre, the male roles fare badly in comparison, with Livingston’s unobservant husband continually out of touch (unless confronted with an impromptu ménage à trois), and Duplass’s self-absorbed, materialistic brother given little to do beyond looking baffled and out of their depth when discussing “women’s issues”. This isn’t necessarily a feminist tract – Marlo makes too many poor choices for that – but it is a celebration of female solidarity, though as the movie unfolds, issues surrounding mental health begin to make themselves more keenly felt. This leads to a last act swerve in the narrative that isn’t completely successful, but at least brings the story to a (by then) predictable conclusion. But Reitman – directing as confidently and intuitively as ever – and Cody, are more focused on Marlo’s journey than her destination, and in that they’re more than successful.

Rating: 8/10 – with Theron and Davis at the top of their game, and in service to a balanced and thoughtful script, Tully is a perceptive look at the perils of motherhood told exclusively from the viewpoint of someone who can’t see those perils for having to deal with them; the kind of indie comedy-drama that rewards viewers in increasingly subtle and unexpected ways, it’s a genuine, ready and willing to please movie that has much to say and which does so very succinctly.